A new update has been updated with a long list of fixes aimed at getting the game to run faster, as well as cleaning up a the connection problems some players are still having.
The patch consists of a long list of technical updates, but the main highlights include performance improvements on dual core systems, and fixes for stuttering that some players were experiencing when loading new sections of a map. There patch also cleans up a number of map glitches and usefully squashes a few exploits like a "fix for infinite supply drop exploit".
The full patch notes are listed on Steam. The game should update itself automatically the next time you play.